Pekka Collin

Tissue transglutaminase autoantibody enzyme-linked immunosorbent assay in detecting celiac disease

BACKGROUND & AIMS Tissue transglutaminase has been reported to be the target for endomysial antibodies in celiac disease. We sought to establish whether immunoglobulin (Ig) A class tissue transglutaminase autoantibodies can be considered specific for celiac disease. METHODS Serum samples from 136 patients with untreated celiac disease (diagnosed according to the criteria of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition) and 207 disease controls were studied. Enzyme-linked immunosorbent assay (ELISA) and Western blots were performed using calcium-treated and untreated tissue transglutaminase as antigen. Reticulin, endomysial, and mouse monoclonal tissue transglutaminase antibodies were studied by an indirect immunofluorescence method and gliadin antibodies with ELISA. RESULTS The calcium-activated tissue transglutaminase autoantibody ELISA was highly sensitive (129 of 136) and specific (194 of 207) in detecting celiac disease. The new autoantibody ELISA test correlated well with the endomysial antibody test. Tissue transglutaminase autoantibody ELISA showed a clearly better predictive potential than the IgA class gliadin antibody ELISA. Immunoblots and ELISA blocking studies showed that calcium is needed for the specific antigen-antibody reaction to occur. Double immunofluorescence staining in human umbilical cord with sera from patients with celiac disease and with monoclonal tissue transglutaminase antibodies showed complete overlap. CONCLUSIONS Calcium-activated tissue transglutaminase autoantibody ELISA is highly accurate in detecting untreated celiac disease. Tissue transglutaminase seems to be the target self-antigen for endomysial antibodies.

Coeliac disease--associated disorders and survival.

The associated diseases in 335 coeliac patients diagnosed 1980-90 were compared with age and sex matched control patients with various gastrointestinal symptoms. Endocrine disorders were found in 11.9% of coeliac and 4.3% of control patients (p = 0.0003). Coeliac patients had insulin dependent diabetes mellitus significantly (p = 0.0094) more often (5.4%) than control patients (1.5%). connective tissue diseases were found in 7.2% of coeliac and in 2.7% of control patients (p = 0.011). Sjögrens syndrome occurred in 3.3% of coeliac patients and in 0.3% of controls (p = 0.0059). Autoimmune thyroid diseases were found in 5.4% and asthma in 3.6% of coeliac patients, but also in 2.7% and 3.6%, respectively, among control patients. The incidences of malignant diseases and the survival rate in coeliac patients were compared with those in the Finnish population. Ten coeliac patients developed a cancer during the follow up (mean 5.3 years, range 1-12) but none had a lymphoma. The risk of malignant diseases in coeliac patients did not differ from that in the Finnish population in general. Eleven coeliac patients died during the follow up. The five year survival rates of coeliac patients did not differ from those in the general population. At least 83% of the coeliac patients adhered strictly to the gluten free diet, which may explain the favourable outcome.

Diagnosing Mild Enteropathy Celiac Disease: A Randomized, Controlled Clinical Study

BACKGROUND & AIMS The diagnostic criteria for celiac disease require small-bowel mucosal villous atrophy with crypt hyperplasia (Marsh III). However, mucosal damage develops gradually and patients may evince clinical symptoms before histologic changes appear. Endomysial antibodies are specific in predicting forthcoming villous atrophy. We hypothesized that patients with mild enteropathy but positive endomysial antibodies benefit from a gluten-free diet (GFD) similarly to patients with more severe enteropathy. METHODS Small-bowel endoscopy together with clinical evaluations was performed in all together 70 consecutive adults with positive endomysial antibodies. Of these, 23 had only mild enteropathy (Marsh I-II) and they were randomized either to continue on a gluten-containing diet or start a GFD. After 1 year, clinical, serologic, and histologic evaluations were repeated. A total of 47 participants had small-bowel mucosal lesions compatible with celiac disease (Marsh III), and these served as disease controls. RESULTS In the gluten-containing diet group (Marsh I-II) the small-bowel mucosal villous architecture deteriorated in all participants, and the symptoms and abnormal antibody titers persisted. In contrast, in the GFD group (Marsh I-II) the symptoms were alleviated, antibody titers decreased, and mucosal inflammation diminished equally to celiac controls (Marsh III). When the trial was completed, all participants chose to continue on a life-long GFD. CONCLUSIONS Patients with endomysial antibodies benefit from a GFD regardless of the degree of enteropathy. The diagnostic criteria for celiac disease need re-evaluation: endomysial antibody positivity without atrophy belongs to the spectrum of genetic gluten intolerance, and warrants dietary treatment.

Selective IgA Deficiency and Coeliac Disease

Twenty-five children and adults with concomitant coeliac disease and selective IgA deficiency are described. IgG-class reticulin antibodies were positive in 94%. The clinical course of coeliac disease did not differ from that of patients with normal serum IgA level. Patients with IgA deficiency also had other concomitant diseases, especially autoimmune diseases. Patients with selective IgA deficiency have at least a tenfold risk of coeliac disease compared with the population in general.

Antiendomysial and antihuman recombinant tissue transglutaminase antibodies in the diagnosis of coeliac disease: a biopsy-proven European multicentre study.

Objective To investigate the value of serum antitissue transglutaminase IgA antibodies (IgA-TTG) and IgA antiendomysial antibodies (IgA-EMA) in the diagnosis of coeliac disease in cohorts from different geographical areas in Europe. The setting allowed a further comparison between the antibody results and the conventional small-intestinal histology. Methods A total of 144 cases with coeliac disease [median age 19.5 years (range 0.9-81.4)], and 127 disease controls [median age 29.2 years (range 0.5-79.0)], were recruited, on the basis of biopsy, from 13 centres in nine countries. All biopsy specimens were re-evaluated and classified blindly a second time by two investigators. IgA-TTG were determined by ELISA with human recombinant antigen and IgA-EMA by an immunofluorescence test with human umbilical cord as antigen. Results The quality of the biopsy specimens was not acceptable in 29 (10.7%) of 271 cases and a reliable judgement could not be made, mainly due to poor orientation of the samples. The primary clinical diagnosis and the second classification of the biopsy specimens were divergent in nine cases, and one patient was initially enrolled in the wrong group. Thus, 126 coeliac patients and 106 controls, verified by biopsy, remained for final analysis. The sensitivity of IgA-TTG was 94% and IgA-EMA 89%, the specificity was 99% and 98%, respectively. Conclusions Serum IgA-TTG measurement is effective and at least as good as IgA-EMA in the identification of coeliac disease. Due to a high percentage of poor histological specimens, the diagnosis of coeliac disease should not depend only on biopsy, but in addition the clinical picture and serology should be considered.

East–West gradient in the incidence of inflammatory bowel disease in Europe: the ECCO-EpiCom inception cohort

Objective The incidence of inflammatory bowel disease (IBD) is increasing in Eastern Europe. The reasons for these changes remain unknown. The aim of this study was to investigate whether an East–West gradient in the incidence of IBD in Europe exists. Design A prospective, uniformly diagnosed, population based inception cohort of IBD patients in 31 centres from 14 Western and eight Eastern European countries covering a total background population of approximately 10.1 million people was created. One-third of the centres had previous experience with inception cohorts. Patients were entered into a low cost, web based epidemiological database, making participation possible regardless of socioeconomic status and prior experience. Results 1515 patients aged 15 years or older were included, of whom 535 (35%) were diagnosed with Crohns disease (CD), 813 (54%) with ulcerative colitis (UC) and 167 (11%) with IBD unclassified (IBDU). The overall incidence rate ratios in all Western European centres were 1.9 (95% CI 1.5 to 2.4) for CD and 2.1 (95% CI 1.8 to 2.6) for UC compared with Eastern European centres. The median crude annual incidence rates per 100 000 in 2010 for CD were 6.5 (range 0–10.7) in Western European centres and 3.1 (range 0.4–11.5) in Eastern European centres, for UC 10.8 (range 2.9–31.5) and 4.1 (range 2.4–10.3), respectively, and for IBDU 1.9 (range 0–39.4) and 0 (range 0–1.2), respectively. In Western Europe, 92% of CD, 78% of UC and 74% of IBDU patients had a colonoscopy performed as the diagnostic procedure compared with 90%, 100% and 96%, respectively, in Eastern Europe. 8% of CD and 1% of UC patients in both regions underwent surgery within the first 3 months of the onset of disease. 7% of CD patients and 3% of UC patients from Western Europe received biological treatment as rescue therapy. Of all European CD patients, 20% received only 5-aminosalicylates as induction therapy. Conclusions An East–West gradient in IBD incidence exists in Europe. Among this inception cohort—including indolent and aggressive cases—international guidelines for diagnosis and initial treatment are not being followed uniformly by physicians.

HLA-DQ typing in the diagnosis of celiac disease

OBJECTIVE:More than 95% of celiac patients share the major histocompatibility complex II class human leukocyte antigen (HLA) DQ2 or DQ8 haplotype; patients negative for both types are unlikely to suffer from celiac disease. Our aim was to investigate whether HLA-DQ2 and -DQ8 typing is helpful when diagnosis is uncertain because of the absence of unequivocal small bowel villous atrophy.METHODS:HLA-DQ2 and -DQ8 typing was carried out in 59 patients evincing nondiagnostic small bowel mucosal lesion or positive celiac serology, and in 17 patients maintaining a gluten-free diet without biopsy-proven celiac disease. HLA findings were compared to small bowel mucosal morphology; intraepithelial lymphocytes; and serum endomysial (EmA), reticulin, tissue transglutaminase (anti-tTG) and gliadin antibodies.RESULTS:Of the 59 patients evincing only minor small bowel mucosal changes or positive celiac disease serology, 22 (37%) were negative for DQ2 and DQ8. All EmA-positive patients had celiac-type HLA, but antireticulin antibody, anti-tTg, and antigliadin antibody were also present in HLA-DQ2– and -DQ8–negative individuals. Eleven of 17 patients (65%) observing a gluten-free diet before small bowel biopsy did not share celiac-type HLA. None of the 17 had apparent villous atrophy. Serum EmA and anti-tTG were negative in all. HLA-DQ typing is less expensive than follow-up biopsy in the exclusion of celiac disease.CONCLUSIONS:HLA-DQ2 and -DQ8 determination is useful in exclusion, probably lifelong, of celiac disease in individuals with an equivocal small bowel histological finding. The low specificity of this test must, however, be borne in mind.

Serological markers and HLA genes among healthy first-degree relatives of patients with coeliac disease

Coeliac disease may remain undiagnosed because of the non-specific nature of the presenting symptoms. Several antibody tests are claimed as markers for this condition but a direct comparison of the available tests has not been reported. The probands and healthy first-degree relatives of 42 families with coeliac disease were studied. Histological examination of biopsy specimens revealed jejunal mucosal villous atrophy compatible with coeliac disease in 13 of 122 relatives. Reticulin-antibody-positive relatives with or without jejunal mucosal atrophy were genetically similar to the probands of the families (DR3 gene frequencies 55.3%-60.0%). Gliadin-antibody-positive relatives with normal mucosa were genetically different from the probands (DR3 gene frequency 16.7% versus 55.3%). IgA reticulin and endomysium antibodies detected 92.3% of subjects with silent coeliac disease. The only case that was missed had selective IgA deficiency and was positive for IgG-class reticulin antibodies. By contrast, gliadin antibodies detected only half of the cases. Follow-up of the 7 reticulin-antibody-positive relatives with normal mucosa revealed 2 further cases of coeliac disease and 1 of dermatitis herpetiformis during the next three years. Our family study shows that healthy reticulin-antibody-positive first-degree relatives of coeliac disease patients, irrespective of the state of the jejunal mucosa, are genetically similar to known coeliac disease patients. Reticulin-antibody positivity is an indicator of both silent and latent coeliac disease.

Osteopenia in patients with clinically silent coeliac disease warrants screening

Bone-mineral density was measured in 19 clinically silent coeliac patients. The density was low, comparable with that in coeliac cases, and improved by gluten-free diet.

Endomysial antibody-negative coeliac disease: clinical characteristics and intestinal autoantibody deposits

Background: Some patients with untreated coeliac disease are negative for serum endomysial autoantibodies (EmA) targeted against transglutaminase 2 (TG2). Aims: To evaluate the clinical and histological features of EmA-negative coeliac disease, and to examine whether EmA-equivalent autoantibodies against TG2 can be seen in the small-bowel mucosa when absent in serum. Patients: Serum EmA was studied in 177 biopsy-proved specimens from adult patients with coeliac disease. 20 patients with intestinal diseases served as non-coeliac controls; three had autoimmune enteropathy with villous atrophy. Methods: Clinical manifestations, small-bowel mucosal morphology, intraepithelial inflammation and TG2-specific extracellular immunoglobulin A (IgA) deposits were investigated in both serum EmA-negative and EmA-positive patients. Results: 22 patients with IgA-competent coeliac disease were negative for serum EmA. Three of these had small-bowel lymphoma. Patients with EmA-negative coeliac disease were older, had abdominal symptoms more often, and the density of γδ+ intraepithelial lymphocytes in their intestinal mucosa was lower than in EmA-positive patients; otherwise the histology was similar. All serum EmA-negative patients with coeliac disease, but none of the disease controls, had gluten-dependent mucosal IgA deposits alongside TG2 in the small-bowel mucosal specimens. In vivo deposited IgA was shown to be TG2-specific by its ability to bind recombinant TG2. Conclusions: Negative serum EmA might be associated with advanced coeliac disease. TG2-targeted autoantibodies were deposited in the small-bowel mucosa even when absent in serum. This finding can be used in the diagnosis of seronegative coeliac disease when the histology is equivocal. It may also be helpful in the differential diagnosis between autoimmune enteropathy and coeliac disease.